Radiographic imaging systems are variously described, for example, in U.S. Pat. No. 4,383,327 of Kruger, U.S. Pat. No. 5,583,904 of Adams, U.S. Pat. No. 6,324,249 B1 of Fazzio, and published U.S. patent application Ser. No. 20040184576 A1 of Meyer. Kruger describes a scanning radiographic system employing a multi-linear array of radiographic sensors operated in a time delay and integration mode. Adams describes a laminography system that allows generation of high speed and high resolution x-ray laminographs using a continuous scan method, two or more linear detectors, and one or more collimated x-ray sources. Fazzio describes a linear scanning geometry laminography system that allows for generation of high speed and high resolution x-ray laminographs using an electronic detector operated in a time-domain integration mode, coupled with a moving source of x-rays. Meyer discloses an x-ray inspection system using a single x-ray source and a planar array of linear sensors that are aligned with their long axes in parallel. In contrast to Adams, in which an article to be inspected makes a single pass over a column of linear sensors, Meyer teaches that an article to be inspected makes a plurality of passes over an array of linear sensors.
Some radiographic imaging systems (e.g., that disclosed by Kruger) are two-dimensional, which means that the relationship between a radiographic source, one or more radiographic detectors, and a specimen to be imaged, enables the imaging of a single plane of the specimen. Other radiographic imaging systems are three-dimensional (e.g., those disclosed by Adams, Fazzio and Meyer), which means that the relationship between the system's radiographic sources, radiographic detectors, and a specimen to be imaged, enables the imaging of multiple planes or a three-dimensional region of the specimen. A three-dimensional imaging system can also enable the construction of a three-dimensional model of the specimen. As a result, three-dimensional systems are often better suited to the inspection of complex or multi-layered specimens, or specimens having features of interest that are obscured by other features.